Evaluating pharmacological THRomboprophylaxis in Individuals undergoing superficial endoVEnous treatment across NHS and private clinics in the UK: a multi-centre, assessor-blind, randomised controlled trial-THRIVE trial.

INTRODUCTION: Endovenous therapy is the first choice management for symptomatic varicose veins in NICE guidelines, with 56-70 000 procedures performed annually in the UK. Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a known complication of endovenous therapy, occurring at a rate of up to 3.4%. Despite 73% of UK practitioners administering pharmacological thromboprophylaxis to reduce VTE, no high-quality evidence supporting this practice exists. Pharmacological thromboprophylaxis may have clinical and cost benefit in preventing VTE; however, further evidence is needed. This study aims to establish whether when endovenous therapy is undertaken: a single dose or course of pharmacological thromboprophylaxis alters the risk of VTE; pharmacological thromboprophylaxis is associated with an increased rate of bleeding events; pharmacological prophylaxis is cost effective. METHODS AND ANALYSIS: A multi-centre, assessor-blind, randomised controlled trial (RCT) will recruit 6660 participants from 40 NHS and private sites across the UK. Participants will be randomised to intervention (single dose or extended course of pharmacological thromboprophylaxis plus compression) or control (compression alone). Participants will undergo a lower limb venous duplex ultrasound scan at 21-28 days post-procedure to identify asymptomatic DVT. The duplex scan will be conducted locally by blinded assessors. Participants will be contacted remotely for follow-up at 7 days and 90 days post-procedure. The primary outcome is imaging-confirmed lower limb DVT with or without symptoms or PE with symptoms within 90 days of treatment. The main analysis will be according to the intention-to-treat principle and will compare the rates of VTE at 90 days, using a repeated measures analysis of variance, adjusting for any pre-specified strongly prognostic baseline covariates using a mixed effects logistic regression. ETHICS AND DISSEMINATION: Ethical approval was granted by Brent Research Ethics Committee (22/LO/0261). Results will be disseminated in a peer-reviewed journal and presented at national and international conferences. TRIAL REGISTRATION NUMBER: ISRCTN18501431.

Pilot study to evaluate hypercoagulation and inflammation using rotational thromboelastometry and calprotectin in COVID-19 patients.

INTRODUCTION: Abnormal coagulation and inflammation are hallmarks of SARs-COV-19. Stratifying affected patients on admission to hospital may help identify those who at are risk of developing severe disease early on. Rotational Thromboelastometry (ROTEM) is a point of care test that can be used to measure abnormal coagulation and calprotectin is a measure of inflammation. AIM: Assess if ROTEM can measure hypercoagulability on admission and identify those who will develop severe disease early on. Assess if calprotectin can measure inflammation and if there is a correlation with ROTEM and calprotectin. METHODS: COVID-19 patients were recruited on admission and ROTEM testing was undertaken daily for a period of 7 days. Additionally inflammatory marker calprotectin was also tested for the same period. RESULTS: 33 patients were recruited to the study out of which 13 were admitted to ITU and 20 were treated on the ward. ROTEM detected a hypercoagulable state on admission but did not stratify between those admitted to a ward or escalated to ITU. Calprotectin levels were raised but there was no statistical difference (p = 0.73) between patients admitted to a ward or escalated to ITU. Significant correlations were observed between FIBA5 (r = 0.62; p<0.00), FIBCFT (r = -0.57; p<0.00), FIBMCF (r = 0.64; p<0.00) and INMCF (r = 0.57; p<0.00) and calprotectin. CONCLUSION: COVID-19 patients were hypercoagulable on admission. The correlations between ROTEM and calprotectin underline the interactions between inflammation and coagulation.

Examining the benefit of graduated compression stockings in the prevention of hospital-associated venous thromboembolism in low-risk surgical patients: a multicentre cluster randomised controlled trial (PETS trial).

INTRODUCTION: Hospital-acquired thrombosis (HAT) is defined as any venous thromboembolism (VTE)-related event during a hospital admission or occurring up to 90 days post discharge, and is associated with significant morbidity, mortality and healthcare-associated costs. Although surgery is an established risk factor for VTE, operations with a short hospital stay (<48 hours) and that permit early ambulation are associated with a low risk of VTE. Many patients undergoing short-stay surgical procedures and who are at low risk of VTE are treated with graduated compression stockings (GCS). However, evidence for the use of GCS in VTE prevention for this cohort is poor. METHODS AND ANALYSIS: A multicentre, cluster randomised controlled trial which aims to determine whether GCS are superior in comparison to no GCS in the prevention of VTE for surgical patients undergoing short-stay procedures assessed to be at low risk of VTE. A total of 50 sites (21 472 participants) will be randomised to either intervention (GCS) or control (no GCS). Adult participants (18-59 years) who undergo short-stay surgical procedures and are assessed as low risk of VTE will be included in the study. Participants will provide consent to be contacted for follow-up at 7-days and 90-days postsurgical procedure. The primary outcome is the rate of symptomatic VTE, that is, deep vein thrombosis or pulmonary embolism during admission or within 90 days. Secondary outcomes include healthcare costs and changes in quality of life. The main analysis will be according to the intention-to-treat principle and will compare the rates of VTE at 90 days, measured at an individual level, using hierarchical (multilevel) logistic regression. ETHICS AND DISSEMINATION: Ethical approval was granted by the Camden and Kings Cross Research Ethics Committee (22/LO/0390). Findings will be published in a peer-reviewed journal and presented at national and international conferences. TRIAL REGISTRATION NUMBER: ISRCTN13908683.

Clinical outcomes and the impact of prior oral anticoagulant use in patients with coronavirus disease 2019 admitted to hospitals in the UK - a multicentre observational study.

Coagulation dysfunction and thrombosis are major complications in patients with coronavirus disease 2019 (COVID-19). Patients on oral anticoagulants (OAC) prior to diagnosis of COVID-19 may therefore have better outcomes. In this multicentre observational study of 5 883 patients (≥18 years) admitted to 26 UK hospitals between 1 April 2020 and 31 July 2020, overall mortality was 29·2%. Incidences of thrombosis, major bleeding (MB) and multiorgan failure (MOF) were 5·4%, 1·7% and 3·3% respectively. The presence of thrombosis, MB, or MOF was associated with a 1·8, 4·5 or 5·9-fold increased risk of dying, respectively. Of the 5 883 patients studied, 83·6% (n = 4 920) were not on OAC and 16·4% (n = 963) were taking OAC at the time of admission. There was no difference in mortality between patients on OAC vs no OAC prior to admission when compared in an adjusted multivariate analysis [hazard ratio (HR) 1·05, 95% confidence interval (CI) 0·93-1·19; P = 0·15] or in an adjusted propensity score analysis (HR 0·92 95% CI 0·58-1·450; P = 0·18). In multivariate and adjusted propensity score analyses, the only significant association of no anticoagulation prior to diagnosis of COVID-19 was admission to the Intensive-Care Unit (ICU) (HR 1·98, 95% CI 1·37-2·85). Thrombosis, MB, and MOF were associated with higher mortality. Our results indicate that patients may have benefit from prior OAC use, especially reduced admission to ICU, without any increase in bleeding.

"I just didn't want to trust it at all": Atrial fibrillation patient's treatment experience of rivaroxaban and warfarin.

BACKGROUND: In the treatment of atrial fibrillation (AF), anticoagulant medications such as warfarin and rivaroxaban are commonly prescribed to reduce the risk of ischaemic strokes, and other thromboembolic events. Research has highlighted advantages and disadvantages of each of these medications, but there remains an absence of qualitative evidence regarding the lived experiences of AF patients. The present study helps address this gap and obtain a greater understanding of the patient experience and beliefs surrounding their anticoagulant medication. METHOD: Semi-structured qualitative interviews with a purposive sample of 20 participants (10 warfarin, 10 rivaroxaban). Interviews were transcribed verbatim and thematically analysed. RESULTS: Data analysis led to the generation of three key themes: positive perceptions of medication, distrust of alternatives, and inconsistencies in support experiences. CONCLUSIONS: Positive perceptions of one anticoagulant medication (ACM) and distrust of alternatives may influence patients' confidence in switching medications. This is potentially problematic where there is a lack of patient engagement in medication changes, as seen during the COVID pandemic. Gaps in patient understanding of anticoagulation, including lack of clarity around medications selection and misconceptions about treatment, were evident. By addressing these misconceptions, clinicians may be better positioned to support people with AF in self-management of their ACM.

Effect of neuromuscular electrical stimulation on the recovery of people with COVID-19 admitted to the intensive care unit: A narrative review.

The rehabilitation of patients with COVID-19 after prolonged treatment in the intensive care unit is often complex and challenging. Patients may develop a myriad of long-term multiorgan impairments, affecting the respiratory, cardiac, neurological, digestive and musculoskeletal systems. Skeletal muscle dysfunction of respiratory and limb muscles, commonly referred to as intensive care unit acquired weakness, occurs in approximately 40% of all patients admitted to intensive care. The impact on mobility and return to activities of daily living is severe. Furthermore, many patients experience ongoing symptoms of fatigue, weakness and shortness of breath, in what is being described as "long COVID". Neuromuscular electrical stimulation is a technique in which small electrical impulses are applied to skeletal muscle to cause contractions when voluntary muscle contraction is difficult or impossible. Neuromuscular electrical stimulation can prevent muscle atrophy, improve muscle strength and function, maintain blood flow and reduce oedema. This review examines the evidence, current guidelines, and proposed benefits of using neuromuscular electrical stimulation with patients admitted to the intensive care unit. Practical recommendations for using electrical muscle stimulation in patients with COVID-19 are provided, and suggestions for further research are proposed. Evidence suggests NMES may play a role in the weaning of patients from ventilators and can be continued in the post-acute and longer-term phases of recovery. As such, NMES may be a suitable treatment modality to implement within rehabilitation pathways for COVID-19, with consideration of the practical and safety issues highlighted within this review.

Compression stockings in addition to low-molecular-weight heparin to prevent venous thromboembolism in surgical inpatients requiring pharmacoprophylaxis: the GAPS non-inferiority RCT.

BACKGROUND: Patients admitted to hospital for surgery are at an increased risk of venous thromboembolism. Pharmaco-thromboprophylaxis and mechanical prophylaxis (usually graduated compression stockings or intermittent pneumatic compression) have been shown to reduce the incidence of venous thromboembolism. The evidence base supporting the National Institute for Health and Care Excellence's recommendation for the use of graduated compression stockings for venous thromboembolism prevention in the UK has recently been challenged. It is unclear if the risks and costs associated with graduated compression stockings are justified for deep-vein thrombosis prevention in moderate- and high-risk elective surgical inpatients receiving low-dose low-molecular-weight heparin pharmaco-thromboprophylaxis. OBJECTIVES: The primary objective was to compare the venous thromboembolism rate in elective surgical inpatients at moderate or high risk of venous thromboembolism who were receiving either graduated compression stockings and low-dose low-molecular-weight heparin (standard care) or low-dose low-molecular-weight heparin alone (intervention). DESIGN: This was a pragmatic, multicentre, prospective, non-inferiority, randomised controlled trial. SETTING: This took place in secondary care NHS hospitals in the UK. PARTICIPANTS: Patients aged ≥ 18 years who were assessed to be at moderate or high risk of venous thromboembolism according to the NHS England venous thromboembolism risk assessment tool (or the trust equivalent based on this form) and who were not contraindicated to low-molecular-weight heparin or graduated compression stockings were deemed eligible to take part. INTERVENTIONS: Participants were randomised 1 : 1 to either low-molecular-weight heparin or low-molecular-weight heparin and graduated compression stockings. MAIN OUTCOME MEASURES: The primary outcome measure was venous thromboembolism up to 90 days after surgery. A combined end point of duplex ultrasound-proven new lower-limb deep-vein thrombosis (symptomatic or asymptomatic) plus imaging-confirmed symptomatic pulmonary embolism. Secondary outcomes included quality of life, compliance with graduated compression stockings and low-molecular-weight heparin during admission, and all-cause mortality. RESULTS: A total of 1905 participants were randomised and 1858 were included in the intention-to-treat analysis. A primary outcome event occurred in 16 out of 937 (1.7%) patients in the low-molecular-weight heparin-alone arm compared with 13 out of 921 (1.4%) patients in the low-molecular-weight heparin plus graduated compression stockings arm. The risk difference between low-molecular-weight heparin and low-molecular-weight heparin plus graduated compression stockings was 0.30% (95% confidence interval -0.65% to 1.26%). As the 95% confidence interval did not cross the non-inferiority margin of 3.5% (p < 0.001 for non-inferiority), the results indicate that non-inferiority of low-molecular-weight heparin alone was shown. LIMITATIONS: In total, 13% of patients did not receive a duplex ultrasound scan that could have detected further asymptomatic deep-vein thrombosis. However, missing scans were balanced between both trial arms. The subpopulation of those aged ≥ 65 years assessed as being at a moderate risk of venous thromboembolism was under-represented in the study; however, this reflects that this group is under-represented in the general population. CONCLUSIONS: For elective surgical patients at moderate or high risk of venous thromboembolism, administration of pharmaco-thromboprophylaxis alone is non-inferior to a combination of pharmaco-thromboprophylaxis and graduated compression stockings. These findings indicate that graduated compression stockings may be unnecessary for most elective surgical patients. FUTURE WORK: Further studies are required to evaluate whether or not adjuvant graduated compression stockings have a role in patients receiving extended thromboprophylaxis, beyond the period of hospital admission, following elective surgery or in patients undergoing emergency surgical procedures. TRIAL REGISTRATION: Current Controlled Trials ISRCTN13911492. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 69. See the NIHR Journals Library website for further project information.

WHY DID WE CONDUCT THIS RESEARCH?: People undergoing operations are at risk of developing blood clots in their legs, which is known as a deep-vein thrombosis. Blood clots occur for several reasons, such as not being able to move around after an operation, changes in the blood or damage to the veins in which blood travels. To decrease the risk of getting deep-vein thrombosis, patients having operations are given tight elastic socks to wear called graduated compression stockings. They are also given blood thinning medicine to prevent clotting. There is little evidence that wearing elastic socks in hospital will reduce the risk of blood clots if blood thinners are also given. Many patients say that the socks can hurt or cause bruising and can be difficult to put on. The graduated compression as an adjunct to thromboprophylaxis in surgery (GAPS) trial investigated whether or not patients having an operation would benefit from wearing elastic socks as well as getting blood thinners, or if blood thinners on their own prevented blood clots. WHAT DID WE DO?: A total of 1905 patients who were having operations at seven hospitals in England agreed to take part. They were randomly assigned to different treatments by a computer program. Half of the patients were given elastic socks plus blood thinners, and the other half were given the blood thinners alone. WHAT DID WE FIND?: There was no significant difference in the number of people who had a blood clot in either study group. This could mean that blood thinners are as good at stopping blood clots as blood thinners and elastic socks for patients having operations. WHAT COULD BE CARRIED OUT NEXT?: The NHS spends around £63M per year across England on elastic stockings. This research indicates that patients might not get extra benefit from wearing them if they have taken blood thinners.

Graduated compression stockings as adjuvant to pharmaco-thromboprophylaxis in elective surgical patients (GAPS study): randomised controlled trial.

OBJECTIVES: To investigate whether the use of graduated compression stockings (GCS) offers any adjuvant benefit when pharmaco-thromboprophylaxis is used for venous thromboembolism prophylaxis in patients undergoing elective surgery. DESIGN: Open, multicentre, randomised, controlled, non-inferiority trial. SETTING: Seven National Health Service tertiary hospitals in the United Kingdom. PARTICIPANTS: 1905 elective surgical inpatients (≥18 years) assessed as being at moderate or high risk of venous thromboembolism were eligible and consented to participate. INTERVENTION: Participants were randomly assigned (1:1) to receive low molecular weight heparin (LMWH) pharmaco-thromboprophylaxis alone or LMWH pharmaco-thromboprophylaxis and GCS. OUTCOME MEASURES: The primary outcome was imaging confirmed lower limb deep vein thrombosis with or without symptoms, or pulmonary embolism with symptoms within 90 days of surgery. Secondary outcome measures were quality of life, compliance with stockings and LMWH, lower limb complications related to GCS, bleeding complications, adverse reactions to LMWH, and all cause mortality. RESULTS: Between May 2016 and January 2019, 1905 participants were randomised. 1858 were included in the intention to treat analysis (17 were identified as ineligible after randomisation and 30 did not undergo surgery). A primary outcome event occurred in 16 of 937 (1.7%) patients in the LMWH alone group compared with 13 of 921 (1.4%) in the LMWH and GCS group. The risk difference between the two groups was 0.30% (95% confidence interval -0.65% to 1.26%). Because the 95% confidence interval did not cross the non-inferiority margin of 3.5% (P<0.001 for non-inferiority), LMWH alone was confirmed to be non-inferior. CONCLUSIONS: For patients who have elective surgery and are at moderate or high risk of venous thromboembolism, administration of pharmaco-thromboprophylaxis alone is non-inferior to a combination of pharmaco-thromboprophylaxis and GCS. These findings indicate that GCS might be unnecessary in most patients undergoing elective surgery. TRIAL REGISTRATION: ISRCTN13911492.

Mechanical prophylaxis, early mobilisation and risk stratification: as effective as drugs for low risk patients undergoing primary joint replacement. Results in 13,384 patients.

INTRODUCTION: Current NICE Guidelines state that all patients undergoing total hip and knee arthroplasty should be given both mechanical and chemical prophylaxis. At our institution, a targeted thromboprophylaxis policy has been in place since October 1999. The aim of this study was to calculate our venous thromboembolism rates and compare these to published rates in the literature. METHODS: All patients are pre-operatively assessed for their VTE risk. Patients are stratified into high or low risk: all patients received mechanical thromboprophylaxis and the higher risk patients now receive chemical and mechanical thromboprophylaxis post op. Patients are reviewed at 2, 6 and 52 weeks and with annual postal questionnaires and clinical and radiological review at 5 and 10yrs. RESULTS: 13,384 primary THA and TKAs were entered into the database. The overall rate of clinically apparent DVT and overall PE rates of 0.48% and 0.42% respectively. 86.16% of our patients were low risk, of these 23.3% of patients were on Aspirin/Clopidogrel with mechanical thromboprophylaxis and 76.7% of patients had mechanical prophylaxis alone. There was no statistical difference between the DVT or PE rates in the low risk groups. CONCLUSION: Our results show that use of early mobilisation and mechanical prophylaxis within an Enhanced Recovery Programme results in comparable VTE rates to chemical prophylaxis for all, which is reflected in the literature. Our results question the need for chemical thromboprophylaxis or extended use of mechanical thromboprophylaxis in "lower risk" patients if a risk stratification policy is used in the context of modern surgical approaches.

Haematological management of major bleeding associated with direct oral anticoagulants - UK experience.

The lack of antidotes for activated factor X-inhibitor direct oral anticoagulants (DOACs) means that management of bleeding consists largely of existing supportive therapies. This study aimed to: (i) examine the relative frequency of DOAC-related major bleeding in relation to DOAC prescriptions over the study period; (ii) describe the presentation and haematological management of DOAC-related major bleeding; and (iii) evaluate the association between the use of prothrombin-complex-concentrate (PCC) and in-hospital mortality. Over a 3-year period, 32 UK hospitals submitted data on haematological management of DOAC-related bleeding. Data consisted of 421 episodes (67%, 21%, 11% and 1% on rivaroxaban, apixaban, dabigatran and edoxaban respectively) of major bleeding on DOACs. The proportion of major bleeds on DOACs and DOAC prescriptions increased throughout the study. Overall, 44% and 37% of patients presented with gastrointestinal bleeding and intracranial haemorrhage (ICH) respectively. Drug concentrations were seldom measured. Compared to no PCC, there was a borderline evidence that receiving low dose PCC (≤25 iu/kg) was associated with better outcomes in terms of mortality (sub-distribution hazard ratio: 0·15; 95% confidence interval: 0·02-1·19; P = 0·07): but this was not the case for higher doses. DOAC concentrations are seldom measured. There was no evidence of benefit for PCC on in-hospital mortality.

A three-year prospective study of the presentation and clinical outcomes of major bleeding episodes associated with oral anticoagulant use in the UK (ORANGE study).

The outcomes of patients developing major bleeding while on oral anticoagulants remain largely unquantified. The objectives of this study were to: (i) describe the burden of major hemorrhage associated with all available oral anticoagulants in terms of proportion of bleeds which are intracranial hemorrhages, in-hospital mortality and duration of hospitalization following major bleeding; (ii) identify risk factors for mortality; and (iii) compare the characteristics of major hemorrhage between cases treated with warfarin and direct oral anticoagulants for the subgroups of patients with atrial fibrillation or venous thromboembolism. This was a multicenter, 3-year prospective cohort study of patients aged ≥18 years on oral anticoagulants who developed major hemorrhage leading to hospitalization. The patients were followed up for 30 days or until discharge or death, whichever occurred first. In total 2,192 patients (47% female, 81% on warfarin, median age 80 years) were reported between October 2013 and August 2016 from 32 hospitals in the UK. Bleeding sites were intracranial (44%), gastrointestinal (33%), and other (24%). The in-hospital mortality was 21% (95% CI: 19%-23%) overall, and 33% (95% CI: 30%-36%) for patients with intracranial hemorrhage. Intracranial hemorrhage, advanced age, spontaneous bleeding, liver failure and cancer were risk factors for death. Compared to warfarin-treated patients, patients treated with direct oral anticoagulants were older and had lower odds of subdural/epidural, subarachnoid and intracerebral bleeding. The mortality rate due to major bleeding was not different between patients being treated with warfarin or direct oral anticoagulants. Major bleeding while on oral anticoagulant therapy leads to considerable hospital stays and short-term mortality.

Dabigatran Versus Warfarin for Direct Current Cardioversion in Atrial Fibrillation.

INTRODUCTION: Direct current cardioversion (DCCV) is considered as the most effective treatment for atrial fibrillation (AF). AF is associated with an increased risk of thromboembolism, and DCCV may increase this risk. The current recommendation is, therefore, to anticoagulate for at least 3 weeks before DCCV and 4 weeks after the procedure. METHODS: A retrospective study of patients referred for elective DCCV as treatment for AF in Hampshire Hospitals NHS Foundation Trust was performed to compare the safety and efficacy of dabigatran with warfarin in this setting. RESULTS: During a 12-month period, 129 patients were referred for DCCV for the treatment of AF and 107 patients received DCCV. Fifty-four patients were anticoagulated with dabigatran, 42 patients with warfarin, and 11 patients with other direct oral anticoagulants (DOACs) with choice of agent determined following an informed discussion with the patient. The average number of days between the date of referral for DCCV and the date of DCCV for patients who were on dabigatran was 51 days, while for warfarin, this was 82 (P = 0.001). The proportion of cancelation and rescheduling for warfarin patients was 21.4%, while for dabigatran, this was 5.5%. Patients were reviewed 6-20 weeks after DCCV; the success rate of DCCV for dabigatran patients was 61%, whilst for warfarin patients, this was 52%. The success rate went up to 69% for patients who received DCCV within 45 days of referral (P = 0.165). CONCLUSION: This retrospective study supports clinical experience that DCCV is more likely to be successful when there is a shorter duration between the onset of AF and the date of DCCV, and shows that the use of dabigatran in comparison with warfarin facilitates earlier DCCV.

In essential thrombocythemia, multiple JAK2-V617F clones are present in most mutant-positive patients: a new disease paradigm.

In essential thrombocythemia (ET), the JAK2-V617F mutation is usually restricted to a subpopulation of neutrophils and platelets, and production of JAK2 wild-type (WT) platelets is not suppressed. Nonmutated precursor cells may, therefore, be susceptible to the acquisition of further JAK2 mutations. We used a common single nucleotide polymorphism (SNP) in the JAK2 coding sequence to genotype V617F alleles obtained either by allele-specific restriction enzyme digestion (RED) or by cloning. Both SNP alleles were detected in JAK2 mutant-positive alleles from neutrophils of 10 of 11 ET patients studied using RED compared with 0 of 5 with polycythemia vera. These results were confirmed in cloned products from 5 ET patients and indicate the occurrence of at least 2 separate JAK2 mutation events in the majority of ET patients investigated. In a further ET patient, JAK2 mutant-positive erythroid colonies with either X-allele inactivated were detected, demonstrating they could not have arisen from a common clonal precursor. These results indicate that at least 2 independent JAK2-V617F events occur commonly in ET patients, and they may arise on a polyclonal background. The presence of a JAK2 mutation in ET patients should not, therefore, be equated with a malignant disease.

Gö6976 is a potent inhibitor of the JAK 2 and FLT3 tyrosine kinases with significant activity in primary acute myeloid leukaemia cells.

Aberrant activation of Janus kinase/signal transducers and activators of transcription (JAK/STAT) signalling is implicated in a number of haematological malignancies and effective JAK inhibitors may be therapeutically useful. We found that Gö6976, an indolocarbazole inhibitor of the calcium-dependent isozymes of protein kinase C (PKC), inhibited interleukin 3/granulocyte-macrophage colony-stimulating factor-induced signalling, proliferation and survival whereas Gö6983, a broad spectrum PKC inhibitor, had no such effects. Gö6976 was found to be a direct and potent inhibitor of JAK2 in vitro. Gö6976 also inhibited signalling, survival and proliferation in cells expressing the leukaemia-associated TEL-JAK2 fusion protein and the myeloproliferative disorder (MPD)-associated JAK2 V617F mutant. In primary acute myeloid leukaemia (AML) cells, incubation with Gö6976 reduced constitutive STAT activity in all cases studied. In addition, Akt and mitogen-activated protein kinase phosphorylation were reduced in 4/5 FLT3-internal tandem duplication (ITD) positive AML cases and 7/13 FLT3-wild-type (WT) cases. Expression of FLT3-WT, ITD and D835Y in 32D cells showed that Gö6976 is also a potent inhibitor of WT and mutant FLT3. In AML cells, Gö6976 reduced the survival to 55 +/- 5% of control in FLT3-ITD cases and to 69 +/- 5% in FLT3-WT samples. These data may help identify clinically useful compounds based on the structure of Gö6976, which can be employed for the treatment of MPDs as well as AML.

-455G/A beta-fibrinogen gene polymorphism, factor V Leiden, prothrombin G20210A mutation and MTHFR C677T, and placental vascular complications.

Hyperfibrinogenaemia is associated with systemic arterial and venous thromboembolism and therefore may contribute to placental vascular disease associated with obstetric complications. The fibrinogen-raising -455G/A beta-fibrinogen gene polymorphism may enhance the physiological increase in fibrinogen levels during pregnancy and thereby predispose to obstetric complications. This retrospective case-control study looked at the association between the beta-fibrinogen gene polymorphism -455G/A, the hereditary thrombophilic markers factor V Leiden, prothrombin G20210A mutation (PGM) and C677T methylene tetrahydrofolate reductase (MTHFR), and obstetric complications associated with placental vascular disease. The study group (n = 247) comprised 147 women (90 Caucasian) who met the clinical criteria and a control group of 100 parous women (90 Caucasian) with no history of obstetric or medical complications. No significant differences were observed in the -455A allelic frequencies of the patient and normal control groups, with (allelic frequencies, 0.156 and 0.178, respectively; P = 0.5716, chi2 test, odds ratio = 1.17, 95% confidence interval = 0.65-2.13) or without (allelic frequencies, 0.129 and 0.170, respectively; P = 0.2077, chi2 test, odds ratio = 1.38, 95% confidence interval = 0.81-2.35) the exclusion of non-Caucasian women. There was an increased prevalence of factor V Leiden among Caucasian patients compared with normal controls (allelic frequencies, 0.056 and 0.017, respectively; P = 0.048, chi2 test, odds ratio = 0.29, 95% confidence interval = 0.05-1.15) but there were no differences in the prevalences of PGM or MTHFR. These data suggest that factor V Leiden is associated with an increased risk of obstetric complications, but that the -455A allele of beta-fibrinogen, PGM and MTHFR do not appear to be implicated.